Sharpening device

ABSTRACT

A blade sharpening device comprising two overlappimg plate-like elements, each defining a respective sharpening edge and being arranged so that a substantially V-shaped sharpening recess is defined between the two sharpening edges. Each plate is individually mounted on a support structure by a pivot means arranged so that the two plates can swing relative to each other and relative to the support structure. The axes of the two pivots are disposed on opposite sides respectively of the sharpening recess and may be substantially parallel to one another or substantially parallel to the sharpening edge of the respective plates. In particular, the pivotal axes are arranged so that the angular relationship between adjacent faces of the two plates varies in accordance with a change in the relative pivotal positions of those plates.

United States Patent [191 Waller 1111 3,861,246 1 Jan. 21, 1975 SHARPENING DEVICE [76] Inventor: Campbell E. Waller, Lot 24 Kent Hughes Rd., Eltham, Australia [22] Filed: Mar. 21, 1974 [21] Appl. No.: 453,422

[30] Foreign Application Priority Data Mar. 26, 1973 Australia 2739/73 52 us. c1 76/86, 76/82, 51/204, 51/214, 30/138 [51] Int. Cl..... 823d 15/00 [58] Field of Search; ..-76/82, 89, 88, 86; 51/214,

51/211 R, 205 WG, 204; 30/138, 139 I [56] References Cited v UNITED STATES PATENTS 2,767,530 10/1956 Paldanius...; 51/214- 2,893,178 7/1959 ORiordan-.. 51/214 3,064,393 11/1962 Chasan 76/86 3,676,961 7/1972 Jackson 51/214 3,774,350 11/1973 Bayly 30/138 Primary ExaminerLeonidas V lachos Attorney, Agent, or FirmDiller, Brown,'Ramik & Wight [57] ABSTRACT A blade sharpening device comprising two overlappimg plate-like elements, each defining a' respectiveparticular, the pivotal axes are arranged so that the angular relationship between adjacent faces of the two plates varies in accordance with a change in the relative pivotal positions of those plates.

8 Claims, 7 Drawing Figures SHARPENING DEVICE This invention relates-to sharpening devices such as -those used .for maintaining a cutting edge on a knife blade, and-althoughthe invention has other applications it will be convenient todescribe it in relation to knife sharpeners.

The invention is applicable to any sharpening device which includes two or more sharpening elements relativelyarranged to act on a knife blade so as to treat opposite sides thereof to create or sharpen the cutting edge of the blade.*A; typical sharpeningdevice of that type includes a pair of elements mounted in or on a support structure, whichmay be formed of a plastics material. Each element is at least partially made from a relatively hard material such as tungsten carbide, or

an abrasive material, and has at least one but preferably two edges arranged .to remove material from .a knife blade and thereby function to sharpen that blade. The two elements are arranged in crossed relationship so that a suitable sharpening angle is formed between their respective sharpening edges. That is, a sharpening recess of /-shape isdefined between the two elements,

and a knife blade is sharpened by locationof the blade' cutting edge within the apex region of that recess and then moving the blade longitudinally across the sharpening elements.

ing operation. If however, the blade is held so as to be skewed to one side relative to that direction, the effectiveness ofat least one of the sharpening elements may be impaired. I

It is an object of the present invention to provide a sharpening device of the general type discussed above in'which the sharpening elements are mounted for relative movement during a sharpening operation. Such a variety of conditions.

' In accordance with theinvention, the overlapping sharpening elements, which are usually in the form of plates, are each individually pivoted to the associated where these features are illustrated in preferred form.

Itis to be understood however, that the essential and optional features of the'invention'are not limited to the specific forms of these features as shown in the drawings:

In the drawings:-

FIG. 1 is alongitudinal cross-sectional view of a typical scabbard to which a sharpening device in accordance with the invention may be applied, and showing one particular embodiment of the sharpening device.

FIG. 2 is an enlarged cross-sectional view taken along lineII-II of FIG. 1.

FIG. 3 is a view similar to FIG. 2 but showing the sharpening elements pivoted away from a rest or neutral position.

FIG. 4 is a cross-sectional view taken along line -IV-IV of FIG. 3. v

FIG. 5 is a plan view of one sharpening element of the deivce shown in FIG. 3, but modified to include biasing means.

FIG. 6 is a view similar to FIG. 5 but showing the biasing means flexed to impose a returning force on the sharpening element. 7

FIG. 7 is a view similar to FIG. 2 and showing an alternative form of sharpening device.

It is to be understood that FIG. 1 is intended to show a typical applicationof the sharpening device, and'does not show the only form of scabbard with which 'thedevice can be used. Nevertheless, the particular scabbard shown has been found to have certain practicaladvantages as are fully explained in Australian Patent'application 36708/71.

The scabbard shown in FIG. 1 includes a housing 2 having a knife receiving passage 3 defined therein. An access opening 4 is provided at one end of the housing 2, and thesharpening device 5 is supported by a carriermember 6 within the passage 3 so as to be located'adjacent to the opening 4. The carrier member 6 is pivotally connected to the housing 2 at a position 7 remote from the access opening 4, and a spring 8 functions to -bias the carrier member 6 towardsan upper wall 9 of the housing 2. In thedrawingflthe carrier member 6 is I shown in the rest position, but it can be pushed down support structure. The axis of each pivot is located on a respective oppposite side of the sharpening recess and is disposed so that the plates will swing generally in the direction of movement of a knife blade engaged in the sharpening recess and moved therethrough for sharpening. In the preferred construction, the axis of each pivot extends substantially parallel to a plane containing the hsarpening recess e.g., the plane of the two overlapping surfaces of the plates when those surfaces are parallel and abutting.

Resilient means may be provided to urge the plates into a rest position, but that is not essential.

The following description refers in more detail to the essential features and further optional features of the invention. To facilitate an understanding of the inveninto a lower position against the action of the spring 8 by insertion of a knife blade into the passage 3 between the sharpening device 5 and upper wall 9.

A reaction member 11 is pivotally mounted on the carrier member 6 ma position 12, and functions to form a guide for a knife blade and to also react with the upper wall 9 so as to assist in initial insertion of a knife blade into the passage 3. That is, a part 13 of the member 11 is engaged by the upper edge of the knife blade and is thereby forced against the wall 9 so that a downwardly directed reaction force is transfered to the carrier member 6 through the pivot connection 12.

As shown in FIGS. 2 to 4 of the drawings, the device 5 includes two sharpening elements 14 pivotally connected to the carrier member 6, which forms the support structure for the device 5. Each element 14 may be formed of a plate or block of tungsten carbide or other suitable material, or combination of materials, but they are preferably plate-like elements as shown in the drawings. The two plates 14 are relatively disposed to define a cutting recesslS as previously described, and the edge surface 16 defining that recess are sharpening edges of the plates 14.

The adjacent broad faces of the two plates 14 overlap so that the sharpening recess 15 is defined between the edges 16 of the plates 14, and in a neutral position of the plates 14, the adjacent broad faces are preferably parallel and abutting. In the construction shown, each plate 14 is secured by adhesive or other appropriate means to a mounting section 17 which is pivotally connected to the carrier member 6 through a pin or trunnions 18. As shown in FIG. 2, the axes of the two pivots extend substantially parallel to each other and the broad faces of the plates 14. Also, each pivot is located remote from the sharpening edge 16 of the associated plate 14. Ribs or walls 19 and 21 are disposed on opposite sides of the plates 14 to limit their swinging movement as shown in FIG. 4, but it will be appreciated that other forms of stop means may be employed.

When a knife blade is located within the sharpening recess 15 and is moved in a direction to effect sharpening, the initial response of the plates 14 is to move with the blade, and that movement may continue until they engage the limit stop 19 or 21 e.g., as shown in FIG. 4. It will be seen from FIG. 4 that the angular relationship of the adjacent broad faces of the plates 14, alters in accordance with the pivotal position of those plates. Such pivotal movement of the plates 14 minimizes the possibility of the knife blade jamming within the recess 15, and the fact that the two plates 14 are indepen: dently movable has the further advantage of permitting the plates 14 to adapt to misalignment between the longitudinal axis of the knife blade and its direction of movement.

Any suitable biasing means may be provided to urge the plates l4'into a central position, orany other neutral position'as may be desired, and one particular arrangement is shown in FIGS. 5 and 6 (only one sharpening plate 14 is shown for convenience of illustration). In that arrangement, a leaf spring 22 is formed integral with or attached to each mounting section 17 and lo cates within an aperture 23 formed within the adjacent side wall 24 of the carrier member 6. When the plate 14 is moved out of the rest position (FIG. 5), the spring 22 is caused to flex as shown in FIG. 6 and thereby imposes a returning force on the plate 14. It will be appreciated that the illustrated arrangement is open to variation, and that other form of biasing means may be employed, whilst still achieving the basic objects of the invention.

A modified form of the invention is shown in FIG. 7, and for convenience of identification parts of that embodiment corresponding to parts of the FIGS. 1 to 4 embodiment, will be given like reference numerals, but of a higher series. The principal distinction of the modified embodiment is that the pivotal axis of each pair of trunnions 1 18 extends substantially parallel to the sharpening edge 116 of the respective plate 114. With this arrangement, a constant sharpening angle is maintained within the recess 115 if the sharpening edges 1 16 are straight, as shown, regardless of the pivotal position of the plates 114. In the embodiment of FIGS. 1 to 4 however, the sharpening angle will vary with movement of the plates 114 on each side of the rest or neutral position, if the sharpening edges 116-are straight. Limit stops corresponding to stops 19- and '21 of the FIGS. 1 to 4 embodiment, are preferably provided in the FIG. 7 embodiment, but only the stop 119 is shown. In addition, the FIG. 7 embodiment may be varied to include biasing means as previously described.

The embodiments of the invention herein described are constructed so that the sharpening elements are operative to sharpen a knife blade during both forward and rearward movement of that blade relative to the sharpening device. In addition, the invention can be applied to a knife scabbard of appropriate construction, such as those shown and described in Australian Patent No. 424,122 and Australian Patent application No. 36708/71.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention as defined by the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A blade sharpening device including two sharpening elements each defining a respective sharpening edge, said elements being arranged in overlapping relationship so that said sharpening edges define a sharpening recess between them, and pivot means connecting each said element to a support structure to permit each said element to move relative to the other, the axis of each said pivot means extending in a direction such that the angular relationship between adjacent surfaces of said overlapping elements varies according to the relative pivotal positions of said elements.

2. A blade sharpening device including at least two sharpening plates each defining a respective sharpening edge, said plates being arranged in overlapping relationship with said sharpening edges extending angularly relative to each other so that a sharpening recess is defined between said edges, pivot means connecting each said plate independently of the other to a support structure to permit relative movement of said plates, the axis of each said pivot means extending substantially parallel of a plane containing said recess, and each said axis being located on a respective opposite side of said recess.

3. A device according to claim 1, wherein the axes of said pivot means extend substantially parallel to each other.

4. A device according to claim 1, wherein the axis of each said pivot means extends substantially parallel to the general direction of the sharpening edge of its respective said sharpening element.

5. A device according to claim 1, wherein stop means is provided on each side of said sharpening elements to limit the degree of movement thereof about said pivot means.

6. A device according to claim 1, wherein biasing means acts on each said element to urge it into a rest position.

7. A knife scabbard including, a housing having a knife receiving passage defined therein; an access opening at one endof said passage; and a sharpening device mounted within said passage adjacent said opening; said sharpening device including, a blade sharpening device including two sharpening elements each defining a respective sharpening edge, said elements being arranged in overlapping relationship so that said sharpening edges define a sharpening recess between them, and pivot means connecting each said element to a support structure to permit each said element to move relative to the other, the axis of each said pivot means extending in a direction such that the angular relationship between adjacent surfaces of said overlapsaid sharpening edges extending angularly relative to each other so that a sharpening recess is defined between said edges, pivot means connecting each said plate independently of the other to a support structure to permit relative movement of said plates, the axis of each said pivot means extending substantially parallel of a plane containing said recess, and each said axis being located on a respective opposite side of said re- CCSS. 

1. A blade sharpening device including two sharpening elements each defining a respective sharpening edge, said elements being arranged in overlapping relationship so that said sharpening edges define a sharpening recess between them, and pivot means connecting each said element to a support structure to permit each said element to move relative to the other, the axis of each said pivot means extending in a direction such that the angular relationship between adjacent surfaces of said overlapping elements varies according to the relative pivotal positions of said elements.
 2. A blade sharpening device including at least two sharpening plates each defining a respective sharpening edge, said plates being arranged in overlapping relationship with said sharpening edges extending angularly relative to each other so that a sharpening recess is defined between said edges, pivot means connecting each said plate independently of the other to a support structure to permit relative movement of said plates, the axis of each said pivot means extending substantially parallel of a plane containing said recess, and each said axis being located on a respective opposite side of said recess.
 3. A device according to claim 1, wherein the axes of said pivot means extend substantially parallel to each other.
 4. A device according to claim 1, wherein the axis of each said pivot means extends substantially parallel to the general direction of the sharpening edge of its respective said sharpening element.
 5. A device according to claim 1, wherein stop means is provided on each side of said sharpening elements to limit the degree of movement thereof about said pivot means.
 6. A device according to claim 1, wherein biasing means acts on each said element to urge it into a rest position.
 7. A knife scabbard including, a housing having a knife receiving passage defined therein; an access opening at one end of said passage; and a sharpening device mounted within said passage adjacent said opening; said sharpening device including, a blade sharpening device including two sharpening elements each defining a respective sharpening edge, said elements being arranged in overlapping relationship so that said sharpening edges define a sharpening recess between them, and pivot means connecting each said element to a support structure to permit each said element to move relative to the other, the axis of each said pivot means extending in a direction such that the angular relationship between adjacent surfaces of said overlapping elements varies according to the relative pivotal positions of said elements.
 8. A knife scabbard including, a housing having a knife receiving passage defined therein; an access opening at one end of said passage; and a sharpening device mounted within the said passage adjacent said opening; said sharpening device including, a blade sharpening device including at least two sharpening plates each defining a respective sharpening edge, said plates being arranged in overlapping relationship with said sharpening edges extending angularly relative to each other so that a sharpening recess is defined between said edges, pivot means connecting each said plate independently of the other to a support structure to permit relative movement of said plates, the axis of each said pivot means extending substantially parallel of a plane containing said recess, and each said axis being located on a respective opposite side of said recess. 